A series of one‐dimensional compression tests was performed at vertical pressures as high as 689 MPa (100,000 psi). Three materials were tested: Ottawa sand, a granulated slag called Black Beauty, and soda lime glass. Glass specimens included three grades of spherical particles and one grade of angular particles. Test results showed how particle crushing is influenced by initial void ratio, particle size, particle angularity, and particle material composition. Three phases of compression behavior were identified: Volume decrease as a result of particle rearrangement at low stresses, characterized by a low “initial” constrained modulus; more intense compression as particles crush and are rearranged extensively under higher stresses; and, as the number of contacts between fractured particles increases greatly at very high stresses, an approach to pseudoelastic behavior characterized by very high values of constrained modulus typical of natural sandstones. Even though the tested specimens varied in mineralogy, initial void ratio, median grain size, particle shape and initial moduli, they showed little variation in final constrained modulus.

Comprehensive measurements of the effective stresses developed during the installation, equalization, and load testing of displacement piles in a loose to medium dense quartz sand are presented. The results shed new light on the mechanisms that control shaft friction in sand. First, it is demonstrated directly that the stresses developed at any given soil horizon depend strongly on both the distance of that horizon from the pile tip and the soil's initial state. Second, pile loading is shown to induce radial effective stress changes associated with the soil fabric set up by installation and dilation phenomena at pile‐soil interface. Thirdly, the operational angles of interface friction are found to be constant volume values that correlate well with the results from laboratory interface shear tests.

Some presently used filter criteria are illogical. Besides satisfying $D_{15}/d_{85}\le 5$ and $D_{15}/d_{15}\ge 4$, both the base and filter materials must possess grading stability when exposed to seepage. There are two reasons for grading instability; scantiness of intermediate grain sizes, which interrupts an internal filter formation process; and loose grains, which move through the void space between fixed grains. A mathematical model for washout of grains and internal filter formation (self‐filtration) in cohesionless materials is developed on the basis of grain and pore geometry considerations and found to agree with results from laboratory tests on sand and gravel mixtures. The model discloses both scantiness and loose grains and predicts the extent of grain washout and the volume decrease caused by the washout. For soils with a large content of fine grains, the hydrodynamic number is shown to have considerable influence on the extent of the washout of grains.

How much gravel should be allowed in low‐hydraulic‐conductivity, compacted soil liners? To address this question, two clayey soils are uniformly mixed with varying percentages of gravel that, by itself, has a hydraulic conductivity of 170 cm/s. Soil/gravel mixtures are compacted and then permeated. Hydraulic conductivity of the compacted gravel/soil mixtures is less than $1\times {10}^{-7}\mathrm{cm}/s$ for gravel contents as high as 50–60%. For gravel contents ≤60%, gravel content is not important: all test specimens have a low hydraulic conductivity. For gravel contents >50–60%, the clayey soil does not fill voids between gravel particles, and high hydraulic conductivity results. The water content of the nongravel fraction is found to be a useful indicator of proper moisture conditions during compaction. From these experiments in which molding water content and compactive energy are carefully controlled, and gravel is uniformly mixed with the soil, it is concluded that the maximum allowable gravel content is approximately 50%.

This paper describes the application of a finite‐element analysis for modeling the top‐down construction of a seven‐story, underground parking garage at Post Office Square in Boston. The analysis incorporates coupled flow and deformations within the soil for real‐time simulation of construction activities; a numerically accurate algorithm for excavation in nonlinear soil; and advanced constitutive modeling of clay behavior. Predictions are evaluated through comparisons with extensive field data, including wall deflections, soil deformations, surface settlements, and piezometric elevations. Differences between predicted and measured wall movements are attributed primarily to postconstruction shrinkage of the roof and floor system, while settlements are affected by unrealistic modeling of piezometric elevations in the underlying rock. A modified analysis, incorporating these factors, greatly improves agreement with the measured data. The results demonstrate that reliable and consistent predictions of soil deformations and ground‐water flow can be achieved by advanced methods of analysis without recourse to parametric iteration, but emphasizes the need for adequate characterization of engineering properties for the entire soil profile.

A three‐dimensional collapse mechanism is described for analysis of the ultimate strength of laterally loaded piles under undrained conditions. The analysis is based on the upper‐bound method of plasticity theory. The mechanism combines a deforming conical soil wedge in the near surface with plane strain deformation at depth. Four optimization parameters are employed, which define the geometrical extent and spatial variation of the soil deformation. The mechanism is capable of rationally accounting for many complexities such as strength non‐homogeneity, soil‐pile adhesion, and suction on the back of the pile. Lateral force and pile top moment loading can both be accommodated. Parameter studies showing the effects of these features are presented along with comparisons of model predictions with recent centrifuge test results. An empirical prediction equation is fit to analytical results for typical soil conditions to provide a more convenient form of the analysis method. The empirical fit is demonstrated for cases of linearly increasing strength and for two‐layered soil systems.

An empirical scaling equation is presented for pseudorelative velocity (PSV) spectral amplitudes in terms of earthquake magnitude, source‐to‐station representative distance, component direction, and local site. Each local site is characterized by both the local soil classification at the recording station (rock, stiff soil, or deep soil) and local geologic condition (depth of sediments). It is shown that both the depth of sediments and the local soil classification have significant different characteristics in different period ranges of the response spectra. Thus, both the local soil classification and the geologic depth of sediments should be used simultaneously in the evaluation of site‐specific response. Using only local soil classification to characterize the local site and ignoring the local geologic conditions may lead to exaggerated estimated PSV amplitudes. The analysis presented will offer to the practicing engineer a useful method of obtaining a more detailed site‐specific PSV response spectra.

The performance of embankment slopes along a section of I‐77 is summarized. Slope failures occurred mostly in embankments constructed of red shales of the Conemaugh, Monongahela, and Washington formations. Soil moisture, soil suction, pore pressure, and slope movements were measured in four embankments. The results of measurements indicated that saturation of the embankment slopes occurred near the surface by infiltration of rainfall. Laboratory shear tests were used to measure the shear strengths of the embankment materials and of the red shales in their intact state and after various manipulations that simulated compaction and weathering. With seepage parallel to the slope, failure could occur if the in‐situ shear strength was close to the lower limit of the peak shear strength measured in laboratory tests on samples of the embankment material. With vertical seepage, failure could occur if the in‐situ shear strength was slightly less than the softened shear strength of samples of intact shale. Since it was not possible to verify the actual seepage conditions, both scenarios are considered possible.

The spatial variability of soil properties in situ is often modeled by trend surfaces and residual variations about trend. With the advent of computer‐aided design, statistical procedures are now routinely applied to trend and residual estimation. A maximum likelihood (ML) technique is presented for simultaneously estimating spatial trends, measurement noise, and the autocovariance structure of residuals about spatial trends. This technique has more favorable statistical properties than traditional procedures, and these properties have an important practical advantage in that they lend themselves to incorporation in computerized data‐analysis systems. Simulation experiments are used to verify small‐sample‐size properties of ML estimation and to draw conclusions on optimal boring layouts. The experiments show that analytical asymptotic properties of maximum likelihood estimators are approached even at the modest sample sizes common in geotechnical site investigations. Field vane strengths from a site‐exploration program are analyzed using the maximum likelihood technique and comparisons are made with results obtained using traditional moment estimators.

Several papers have been written about the influence of structural stiffness on soil consolidation. Most dealt with the soil as an elastic-medium, flexible beam on a Winkler medium with adequate interface finite element between the structure and soil, foundation element stiffness matrix, and three-phase spatial structure. The present technical note considers the effect of settlement caused by cohesive soil consolidation on the structure and the effect of the change in structure forces on the process of consolidation. It also considers the direct pressure from the foundation on the soil, as well as the pressure spread according to Boussinesq's equation from one foundation to another.

To evaluate the effect of mining-induced subsidence on a proposed coal refuse embankment, a two-step, combined empirical/finite element (FE) analysis was conducted. A maximum ground surface subsidence profile was obtained from an empirical prediction algorithm incorporated into a commercially available computer code. The predicted ground displacements were then input as boundary conditions in the FE analysis. A nonlinear elastic material model was utilized to represent the coarse refuse and cohesive fill portions of the dam. The analysis provided an estimate of the location and magnitude of settlement on the dam crest, and indicated the portions of the dam that may be highly stressed. The results located portions of the fill that may require attention during construction, and delineated areas of the dam where instrumentation or periodic field inspection will be needed.